Protein aggregation behavior and structural characteristics in a lipoxygenase-linoleic acid-wheat gluten model system

This study explores the synergistic effects of linoleic acid (LA) oxidation on the aggregation behavior and structural properties of wheat gluten (WG). Using lipoxygenase to induce LA oxidation, it was observed that this process significantly influenced WG's viscoelasticity and structural characteristics. Specifically, LA oxidation enhanced WG's viscoelastic properties while reducing its instantaneous elastic and recovery deformations. The optimal viscoelasticity occurred with 0.1 mL/g of LA and a reaction time of 60 min. From the perspective of aggregation behavior, increasing LA concentration reduced hydrophobic interactions while significantly boosting disulfide bond formation and stabilizing secondary structures such as α-helices and β-sheets. Complementary analyses using SE-HPLC and RP-HPLC confirmed that LA oxidation intensified the covalent aggregation of WG. Furthermore, confocal laser scanning microscopy revealed that LA oxidation resulted in a more homogeneous WG structure, characterized by smaller pore sizes and more branched gluten networks. In conclusion, the oxidation of LA effectively promotes covalent cross-linking in WG, leading to improved structural and functional properties. These findings provide valuable insights into the oxidation mechanisms of WG and potential strategies for modulating its properties in food applications.